Chapter Exam

Chapter 12: Ecosystem — Online MCQ Test

Q: Which of the following is an abiotic component of an ecosystem?

Answer: C. Temperature — Abiotic components are non-living factors such as temperature, light, water and soil. Producers, consumers and decomposers are biotic components.

Q: The vertical distribution of different species occupying different levels in an ecosystem is called:

Answer: A. Stratification — Stratification refers to the vertical layering of organisms, such as trees, shrubs and herbs in a forest ecosystem.

Q: If the gross primary productivity of an ecosystem is 1200 kcal m−2 yr−1 and respiration loss is 500 kcal m−2 yr−1, what is its net primary productivity?

Answer: B. 700 kcal m−2 yr−1 — NPP = GPP - R. Therefore, NPP = 1200 - 500 = 700 kcal m−2 yr−1.

Q: A forest has many plant layers such as tall trees, smaller trees, shrubs and herbs. This is an example of:

Answer: B. Stratification — Vertical layering of vegetation in a forest is called stratification, a structural feature of ecosystems.

BIOLOGY · Grade 12 · CBSE(NCERT)

Practice Chapter 12: Ecosystem with a free chapter-wise online MCQ test for CBSE(NCERT) Grade 12 BIOLOGY. This chapter covers: Ecosystem Biotic Components Abiotic Components Food Chain Food Web Energy Flow Ecological Pyramid Primary Productivity Decomposition Nutrient Cycling Biomass. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 12: Ecosystem — Important Questions & Answers (FAQ)

Frequently asked questions from CBSE(NCERT) Grade 12 BIOLOGY — Chapter 12: Ecosystem, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which of the following is an abiotic component of an ecosystem?

A. Producers
B. Decomposers
C. Temperature ✓
D. Consumers

Answer: C. Temperature
Abiotic components are non-living factors such as temperature, light, water and soil. Producers, consumers and decomposers are biotic components.

The vertical distribution of different species occupying different levels in an ecosystem is called:

A. Stratification ✓
B. Decomposition
C. Mineralisation
D. Leaching

Answer: A. Stratification
Stratification refers to the vertical layering of organisms, such as trees, shrubs and herbs in a forest ecosystem.

If the gross primary productivity of an ecosystem is 1200 kcal m−2 yr−1 and respiration loss is 500 kcal m−2 yr−1, what is its net primary productivity?

A. 500 kcal m−2 yr−1
B. 700 kcal m−2 yr−1 ✓
C. 1200 kcal m−2 yr−1
D. 1700 kcal m−2 yr−1

Answer: B. 700 kcal m−2 yr−1
NPP = GPP - R. Therefore, NPP = 1200 - 500 = 700 kcal m−2 yr−1.

A forest has many plant layers such as tall trees, smaller trees, shrubs and herbs. This is an example of:

A. Nutrient leaching
B. Stratification ✓
C. Humification
D. Energy loss

Answer: B. Stratification
Vertical layering of vegetation in a forest is called stratification, a structural feature of ecosystems.

Which statement about the carbon cycle and phosphorus cycle is correct?

A. Both have atmosphere as their main reservoir
B. Carbon cycle is sedimentary and phosphorus cycle is gaseous
C. Carbon has a major atmospheric component, while phosphorus mainly cycles through rocks and sediments ✓
D. Phosphorus is released in large amounts through respiration like carbon dioxide

Answer: C. Carbon has a major atmospheric component, while phosphorus mainly cycles through rocks and sediments
Carbon cycling involves the atmosphere mainly as carbon dioxide, while phosphorus has its major reservoir in rocks and sediments.